1. Field of the Invention
The present invention relates to a developer material holding apparatus, a process cartridge to which the developer material holding apparatus is attached, and an image forming apparatus to which the process cartridge is attached.
2. Description of the Related Art
Some conventional image forming apparatuses use a powder developer material, e.g., toner. A toner cartridge holds a developer material or toner therein, and is detachably attached to a process cartridge of the image forming apparatus. The toner cartridge includes a casing that defines a toner chamber, and a shutter that is rotatably accommodated in the casing. The casing includes a toner discharging opening formed therein, and the shutter includes another toner discharging opening formed therein. The openings are substantially equal in size. When the shutter is rotated relative to the casing to a position where the toner discharging openings are in alignment with each other the toner is discharged from the toner chamber into the process cartridge of the image forming apparatus. JP 2006-243446 discloses one such toner cartridge.
The conventional toner cartridge is mounted on top of the process cartridge, so that the toner is discharged through the toner discharging opening formed in the casing into a toner receiving opening formed in the process cartridge. Thus, the whole toner in the toner cartridge directly exerts pressure on the toner in the process cartridge, so that the toner in the process cartridge is compressed.